Sunday, January 01, 2006

Aircraft litter seafloor off S. O'ahu

An undersea aircraft museum lies on the ocean floor off South O'ahu, and it includes representatives of virtually the entire era of the flying boats — from early post-World War I biplanes to World War II PBY Catalinas and a postwar behemoth that sank in 1950, the Martin Marshall Mars.A University of Hawai'i deep-submersible vehicle, right, approaches the hulk of an old Navy PD-1 flying boat in waters off Pearl Harbor, where a virtual undersea aircraft museum has been found. NOAA/HURL photo

The National Oceanic and Atmospheric Administration yesterday announced a series of discoveries made last week and said agencies are mapping the sea-floor to document the area's collection of ships, planes and other maritime archaeological finds.

"Flying boats had a special significance for Hawai'i and the Pacific islands. They were the only way to get between the islands by air before the development of airports," said marine archaeologist Hans Van Tilburg, of the NOAA National Marine Sanctuary program. "The first interisland air transportation in Hawai'i was in flying boats."

The seafloor region off Pearl Harbor may be better known for its ships, like the Japanese miniature submarine that was sunk an hour before the Dec. 7, 1941, attack on Pearl Harbor. The sub's wreckage was found in 2002.

But there's lots more on a bottom of silt and rock in water 1,000 feet deep and extending several miles from the entrance to Pearl Harbor. The deep water has currents but not a lot of turbulence, and many of the aircraft are in remarkable shape, Van Tilburg said.

Some planes have been wrecked. Some have been taken out and dumped, including at least six former PD-1 Navy bi-plane flying boats. The giant Marshall Mars flying boat sank April 5, 1950, after it landed safely with an engine fire and offloaded its crew before the plane exploded.

Between them, they represent the earliest years of flying boats, and what some might term the pinnacle of the genre.The twin-wing PD-1 designs date to the 1920s. Van Tilburg said a squadron of them flew as patrol craft out of Ford Island in Pearl Harbor. He has found no records of their disposal, but the fact that their fuselages are complete and that wheels are attached suggest they did not fly to their watery ends and were probably dumped, he said.

PBY Catalinas, which served as Navy patrol, rescue and bombing workhorses during World War II, have also been spotted on the bottom off Pearl Harbor.

During the war, the government was looking for ways to get lots of soldiers and gear long distances to places without airports. Size mattered, and new designs dwarfed the little patrol planes.

The Marshall Mars was one of a half-dozen huge flying boats built by the Martin aircraft firm as cargo and personnel carriers after World War II. It was the same era when Howard Hughes was building his famed Spruce Goose. The Mars planes had 200-foot wingspans — roughly the same as that of a 747.

They were named for the Pacific island groups they served: the Marshalls, Carolines, Marianas, Philippines and Hawai'i. Two Hawai'i Mars planes were built. The second is still flying, hauling water to forest fires in the Pacific Northwest.

George Hutton, of Chipley, Fla., who worked on the planes as a radioman in the mid-1940s, said they were comfortable and roomy.

"It was a big, big, monstrous plane, but it was a good plane. You felt very safe in it. There were several decks and you could go up and down circular stairways," Hutton said.

He said he flew one long mission across the Pacific on the Marshall Mars before its fatal flight, in which it landed in the ocean off Honolulu with its No. 3 engine afire. The crew got off in rubber boats, but the fire spread, and the plane exploded, in full view of folks from Waikiki to Pearl Harbor, Van Tilburg said. The plane sank and was lost until a few pieces were located in an undersea survey in August this year. The main wreckage was found in dives on Thursday and Friday.

The history of the region off Pearl Harbor is being prized from the ocean floor by a collaboration of NOAA's National Marine Sanctuary Program, the National Park Service and the University of Hawai'i's Hawai'i Undersea Research Laboratory (HURL), which operates the twin deep-diving submersibles Pisces IV and V.